Flat panel displays (FPDs) are widely used in various modern electronic products due to the advantages of low radiation and low power consumption. Some kinds of display panels, for example, liquid crystal panels, are passive optical devices, which are incapable of emitting light beams themselves. In order to enable these kinds of display panels to display images, in general, backlight modules are introduced in the FPDs as to provide sufficient illumination for the display panels.
Referring to FIG. 1, a typical FPD 100 comprises a display panel 101 and a backlight module 102. The backlight module 102 comprises a light source 110, a light guide plate (LGP) 120, an optical film assembly 130, and a reflector film 140. The LGP 120 comprises a bottom surface 121, a light emitting surface 122 opposite to the bottom surface 121, and a light incident surface 123 adjoining both the bottom surface 121 and the light emitting surface 122. The light source 110 is located adjacent to the light incident surface 123, and the reflector film 140 is located adjacent to the bottom surface 121. The optical film assembly 130 generally comprises an upper diffuser 131, a brightness enhance film (BEF) 132, and a lower diffuser 133 disposed between the light emitting surface 122 and the display panel 101 in that order from top to bottom.
The optical film assembly 130 is adapted to convert light beams emitting from the LGP 120 into uniform planar light. Typically, the BEF 132 employs micro-lens structures to gather the light beams, so as to enhance the brightness of the backlight module 102. The diffusers 131, 133 are used to scatter the light beams transmitted thereto, such that the planar light provided to the display panel 101 can be uniform.
As can be seen, in order to obtain the uniform planar light, it is needed to adopt various optical films in the backlight module 102, for example, the BEF 132 and the diffusers 131, 133. The variety of optical films may cause a structure of the backlight module 102 to be complicated, and additionally, a cost of such complicated backlight module 102 is high.